I picked up some used VR4s and had the upgrade; I'm very, very happy with the improvement. It's simply amazing. YMMV, mine were older than the most current VR4's. I can't compare the new HSE's to the 4/5 upgrade, since I haven't heard the HSE.
As far as the upgrade's impact on my old VR 4: Everything is better! I love it. I took the time to break them in, and it makes a huge difference. I've listened to a lot of $$$ speakers, including the Meadowlarks, that just don't compare IMHO. I am hereby out of the market for speakers; there's nothing even close to how great these are for the price. If I had a friend looking for good speakers in the <$10k category, these would be my recommendation.
As far as the upgrade's impact on my old VR 4: Everything is better! I love it. I took the time to break them in, and it makes a huge difference. I've listened to a lot of $$$ speakers, including the Meadowlarks, that just don't compare IMHO. I am hereby out of the market for speakers; there's nothing even close to how great these are for the price. If I had a friend looking for good speakers in the <$10k category, these would be my recommendation.